ATL: INVEST 99L - Models

[TomballEd]

Not many, but a few of the GFS and Euro ensembles see this in the Caribbean. The Canadian ensembles look 10% positive for the Gulf or Caribbean.

[Teban54]

The fact that it's the Euro ensembles that show Caribbean potential, and not the GFS suite (which can often be trigger-happy with Caribbean developments), is a little bit concerning regardless of how weak the signal is.

We'll see whether this continues.

[Stratton23]

Teban54 why is that concerning?

[DunedinDave]

The fact that it's the Euro ensembles that show Caribbean potential, and not the GFS suite (which can often be trigger-happy with Caribbean developments), is a little bit concerning regardless of how weak the signal is.

We'll see whether this continues.

The good news is it’s only like, what, 3 out of a hundred? Not saying this system should be discounted but right now I think the odds are good for it being a fish. Still worth keeping an eye on though.

[Stratton23]

Even though its still a low chance, 12z AIFS/ EPS ensembles and even a couple GEPS members still have some sort of system out of this getting into the gulf, if this were to develop by chance, this definitely wouldn’t recurve because its at such a low latitude and high pressure is building to its north, just something to watch, we have seen surprises in the western caribbean before from waves that dont do much at first

[LAF92]

Would the storm in the gulf on the gfs 18z be from the wave of 99L?

[Stratton23]

00z hurricane model intensity forecast is in, several are now showing 99L becoming a hurricane, i smell potentially a huge muss by the global models on this one

[LAF92]

00z hurricane model intensity forecast is in, several are now showing 99L becoming a hurricane, i smell potentially a huge muss by the global models on this one

What timeframe are they showing it gaining that much intensity?

[cycloneye]

[Woofde]

00z hurricane model intensity forecast is in, several are now showing 99L becoming a hurricane, i smell potentially a huge muss by the global models on this one

Yeah it's definitely unusual to see such a gap between the SHIPS model and the globals. I wonder if we will see an uptick in intensity amongst the globals once 0z runs comes out. 99L does look good so it wouldn't be too surpising.

[Hurricaneman]

This may not dissipate like models are saying, might be something to watch for the southern lesser Antilles if the hurricane models are to be believed

[Sciencerocks]

I am starting to see hints that this could become a hurricane in the caribbean and probably ride up the trough's back side into the gulf. I'd estimate probably 70% of this. It is already a organized system and I extremely doubt it will just fall apart.

[Pelicane]

Notable increase in the 850 mb vorticity signature on the 0z GFS as this passes through the Lesser Antilles. Very important to follow it in real-time since the models may not be seeing its current structure very well.

[chaser1]

Notable increase in the 850 mb vorticity signature on the 0z GFS as this passes through the Lesser Antilles. Very important to follow it in real-time since the models may not be seeing its current structure very well.

https://www.tropicaltidbits.com/analysis/models/gfs/2025082200/gfs_z850_vort_eatl_20.png

Good observation and very good point. I'm pretty sure one of the elements that NHC was (and is) anticipating to mitigate further development and ultimately dissipate 99L, is the visible Easterly surge of very dry air rushing westward. Curiously, 99L's WSW motion has thus far preserved the integrity of what I believe is a rather tight COC. We'll see if this relative discreet disturbance can maintain its identity while laying low and sliding west long enough for the Easterly surge to potentially spread out and moderate.

[Nimbus]

There is still an ULL to the west of 99L which was forecast to shear it apart.
The NHC is seeing this making it through the shear before the Caribbean and the forecast now is for more favorable conditions near the Antilles.
Looks like a sharp wave still attached to the surface trough to its north.

[Stratton23]

12z ICON tries to consolidate into a TC as 99L gets near or just past the leeward islands

[hurricane2025]

Icon is now on board

[LAF92]

Icon is now on board

Is it just me or does the ICON speed up the storms track

[Stratton23]

GFS still just buries this into CA, CMC is a bit more interesting, the wave can be tracked all the way into the bay of campache, doesn’t develop but interesting to see the wave does hold together on the CMC

[TomballEd]

GFS still just buries this into CA, CMC is a bit more interesting, the wave can be tracked all the way into the bay of campache, doesn’t develop but interesting to see the wave does hold together on the CMC

I think if the Canadian is extrapolated past 240 hours, it would develop an EPAC storm.